Field
Embodiments described herein generally relate to a method and apparatus for processing semiconductor substrates, more particularly, to a method for plasma treating a process chamber.
Description of the Related Art
Integrated circuits (ICs) are composed of many, e.g., millions, of devices such as transistors, capacitors, and resistors. Transistors, such as field effect transistors (FETs), typically include a source, a drain, and a gate stack. The gate stack generally includes a substrate, such as a silicon substrate, a gate dielectric, and a gate electrode, such as polycrystalline silicon, on the gate dielectric. The gate dielectric layer is formed of dielectric materials such as silicon dioxide (SiO2), or a high-k dielectric material having a dielectric constant greater than 4.0, such as SiON, SiN, hafnium oxide (HfO2), hafnium silicate (HfSiO2), hafnium silicon oxynitride (HfSiON), zirconium oxide (ZrO2), zirconium silicate (ZrSiO2), barium strontium titanate (BaSrTiO3, or BST), lead zirconate titanate (Pb(ZrTi)O3, or PZT), titanium nitride (TiN) and the like. In some cases, the gate dielectric includes a stack of dielectric layers, such as SiO2/HfO2/TiN stack disposed on the silicon substrate. It should be noted, however, that the film stack may include layers formed of other materials.
Defects such as atomic vacancies are common in the dielectric layers, for example, O vacancies in HfO2 layer. Other defects such as interfacial defects (dangling bonds for example) are also common in various interfaces such as TiN/HfO2 or HfO2/SiO2. Atomic vacancies and interfacial defects can cause leakage, thermal instability, mobility instability, and transient threshold voltage instability. Therefore, an improved apparatus and method are needed.